Sinker cam for knitting machines



Feb. 7, 1939. R. H. LAWSON ET AL 2,145,986

SINKER CAM FOR KNITTING MACHINES Filed Aug. 4, 1936 2 Sheets-Sheet l l VIII/[ ,1]

72 r y f b Feb. 7, 1939. R H, LAWSON ET AL 2,145,986

SINKER CAM FOR KNITTING MACHINES Filed Aug. 4, 1936 2 Sheets-Sheet 2 F1613 F1013. Mi

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Patented Feb. 7, 1939 UNITED STATES PATENT OFFICE SINKER CAM FOR KNITTING MACHINES setts Application August In C 4, 1936, Serial No. 94,217

anada September 27, 1935 IClaims.

This case deals with improvements in sinker cams for knitting machines wherein the sinkers are movable in opposition to the movement of the needles for participating in stitch drawing. More specifically, the invention comprises certain attachments for use with a sinker cam of the type described to take up excessive movement of the sinker due to improper fitting of parts, wear, etc.

In the drawings:

Fig. 1 is a section showing atypical machine of the type wherein the invention is employed;

Fig. 2 is a plan view showing a sinker cam assembly for the machine illustrated in Fig. 1, the invention being illustrated therewith;

Fig. 3 is an elevation of a sinker cam and the sinker pressing spring functioning therewith;

Fig. 4 is a section through the cam illustrated in Fig. 3;

Figs. 5 and 6 are details 01' the sinker pressing spring;

Figs. '7, 8 and 9 illustrate a modified form of the invention;

Figs. 10 and 11 illustrate another'modification; and

Figs. 12 and 13 show in detail the pivot about which the pressing spring of the last modification swings.

Referring to Figs. 1 and 2 we have illustrated certain essential parts of a multi-feed knitting machine wherein needles and sinkers move in opposed directions for the purpose of measuring and drawing stitches when forming knitted fabric. In these illustrations a rotatable needle cylinder is shown at l, needles 2 and jacks 3 being arranged for reciprocation in slots therein which are'made up of hardened strips one of which is illustrated at 4. It is not necessary that the needle cylinder be built up in this manner, neither is the invention limited to rotating needle cylinders but may be employed in machines wherein the cylinder is stationary with cams rotating relatively thereto. A supporting ring 5 is clamped in the usual manner to rotate with the cylinder and has slots therein in alignment with other slots in a stitch ring 6, sinkers 1 being guided within these slots to pivot at the base of the shank when drawing stitches and for moving radially at the proper time. Each of these sinkers has a lower projection 8 to which the upper ends of jacks connect.

A cam block generally designated at 9 has cams I0 and H for engaging needle butts and causing those needles to draw stitches. Said block also has attached thereto cams l2 and II for e ing butts on the jacks to move them at the proper time for causing sinkers to participate in this stitch drawing movement. For a complete disclosure of these cams and their function reference is made to United States application No. 4

34,579, filed in the names of Lawson and Smith.

A sinker cam assembly is attached by ,means of screws ll to the upper end of said cam block 9 and consists of a plate IS, an angular portion l6 and cams attached thereto. One cam i1 is fixed to the inner end of plate I! by means of screws l8. Another cam i9 is fixed to a lever which pivots about point II for the purpose of being adjusted by means of a thumb nut 22 threaded on spindle 23, said spindle terminating at the inner end in a head portion 24 for engaging cam I9. A spring 25 keeps this head 24 in engagement with cam l8 and will project that cam in towards the central part of the machine as far as the adjustment of thumb nut 22 will permit. This adjustment is similar to that described in the United States application above mentioned and will not be described to greater extent in this case.

Another cam 26 is pivoted at 21 to a lever 28 which is in turn capable of rotating about the shoulder screw 2 on lever 20. This cam It bears against butts 30 on the sinkers and maintains them in an inward direction after they have passed beyond cams I 1 and I9. An eccentric 3! is rotatable on screw 32 and also capable of being locked in position by the same, this eccentric bears against lever 28 for the purpose of adjustably limiting the movement of that lever and cam 26 inwardly oi the machine. Lever 28 has an extension 33 to which has been attached a collar 34. A spring 35 attaches to pin 36 and to collar 34 for holding the cam 26 inwardly as far as the adjustment of eccentric 3i will permit. By movement of collar 34 along the arm 33 it is possible to vary the tension in spring 35.

While drawing stitches the needles are compelled to move in a restricted pathway by means of cams i0 and Ii; sinkers l are at the same time moved in the reverse direction by means of cams l2 and I3 but the movement given sinkers involves much greater acceleration than does the movement of needles. When sinkers, jacks 3 and cams l2 and I3 are new and thus fitted to very close limits, there will be an exact movement of sinkers such as was contemplated by the designer of the machine. However, it is inevitable that the cams as well as the nibs on the uppr end 01 the jack which engage about projection 8 planned. The inertia of the rapidly :moving sinkers causes themto move farther than the Jacks actually raise them; this is true in the machine illustrated since the fabric does not hang on the sinkers. This movement generally termd "firing" will vary for each cam spaced about the multi-feed machine, for different amounts of wear between jacks and cooperating sinkers, due to varying amounts of frictionand for other reasons. Cam I! normally fits rather closely on the tops of sinker shanks but it is necessary to have suiiicient clearance at this point so that no binding will ever take place. I'br these reasons we have constructed a spring 31 of particular shape to attach to cam l1 and bear upon the tops of these sinker shanks.

This spring 31 is better shown in Figs. and 8 and is attached to cam II by means of theme screws I! which pass through plate I! and thread into the cam. This spring has a forward slant edge 38 and a lower part 39 which inclines as shown in Fig. 6 when relieved of tension. The

cam" is cut away as shown at 40 so that the portion 39 of the spring may fit therein if necessary due to being fiexed upwardly to an excessive degree. In Fig. 4 plate i5 and cam I! are shown in section while the spring is shown in its normal position as a series of sinkers are passing beneath it.

It will be evident from the foregoing that spring 31 will not interfere with the normal action of other elements but will always serve to limit the upward movement of sinkers as governed by the jacks, and will prevent any firing of sinkers which has proved to be a very troublesome cause of knitting streaked fabric due to the uneveness of stitch drawn.

Referring to Figs. 7, 8 and 9 we will describe a modified form of the invention wherein a cam i1 similar to cam I! is attached to a plate ii. This cam I1 is cut away in the same manner cam I! was and a spring 4| having an upturned portion 42 fits beneath this cut out portion to serve the same purpose which was served by spring 31. A leaf spring 43 is attached by screw 44 to the plate and is slotted at its free end to engage the upturned part 42 as illustrated. A projection 45 has an adjusting screw 46 threaded therethrough and bearing against the top of the plate to adjust the elevation of the leading edge or spring 4i. Leaf spring 43 provides for this leading edge of the sinker pressing spring moving upwardly if such movement becomes essential. A lock nut 41 serves to maintain the adjusting screw 48 in whatever position it is set.

. A coil spring 4! is attached at the upper end of the upturned portion 42 and also to a pin 4! fixed in the cam. This spring is under sufilcient tension to rock the pressing spring 4| about the slot in the end of leaf spring 43 thus tending to cause the tail of spring 4| to bear downwardly inst the tops of sinkers. It will be seen that this spring 41 will serve to hold sinkers downwardly to prevent firing as previously described.

Referring to Figs. 10, 11, 12 and 13 a second modification is shown wherein plate I!" has attached thereto a cam 50 slightly different from cam II but serving'the same purpose. This cam 50 is cut away in the manner described with respect to those previously mentioned but has a forward end slotted in both a vertical and horizontal direction. Within the vertical slot an upturned portion ll of a spring 52 is free to pivot about a pin 84 passing through the horizontal slot. Pin 84 is cut away as illustrated in Figs. 12 and 13 so that the upturned portion 5| can be soldered or otherwise connected to the pin, and willrock thereon as the pin rotates in its horirental slot. A hooked end II has attached thereto a spring I the other end of which is secured to pin II; this spring serves to rock. this sinker pressing spring in a direction to make it bear downwardly on sinkers for the same reason disclosed with respect to springs 39 and 4|.

This invention has been described with respect to a multi-feed machine of a particular type merely for illustrative p p ses and it is to be understood that we are not limited particularly to multi-feed machines nor are we limited to sinkers operated by jacks oi the particular type herein disclosed, but the invention may be employed with any knitting machine wherein sinkers participate in the drawing of' stitches and there is a possibility of firing as previously described.

What wedesire to protect as our invention is defined in the claims appended hereto. We claim:

1. In a knitting machine, a series of needles and sinkers functioning-to draw loops and knit fabric, said sinkers being moved upwardly to participate in measuring and drawing said loops, Jacks connected at their upper ends to said sinkers and having butts at their lower ends for engaging said cams for giving to said sinkers a predetermined amount of upward movement, and

resilient meansfunctioning on the tops of said sinkers for preventing movement beyond that originally provided by said jacks.

2. A sinker cam assembly for use with knitting machines of the type described including a cam positioned to bear upon upper surfaces of sinkers, said cam having an inclined leading edge and a spring member attached to said cam and presenting an elongated surface beneath the cam for resiliently pressing downwardly upon said sinkers.

3. A sinker cam as defined in claim 2, wherein said spring member is inclined to correspond with the inclined edge of the cam itself and wherein the portion of said cam bearing upon sinkers inclines downwardly when untensioned.

4. A sinker cam assembly for use with knitting machines of the type described including a cam for bearing upon the upper surfaces of sinkers, a

spring member pivoted at the leading edge of said cam and resilient means for rocking said spring member about its pivot for the purpose of pressing said spring member downwardly against the upper surfaces of sinkers.

5. A sinker cam as defined in claim 4, further characterized in that the leading edge of said spring member is also pressed downwardly by a second resilient element.

6. A sinker assembly for use with knitting machines of the type described including a support, a cam for bearing on the upper edges of sinkers, a pivot at the forward or leading edge of said cam, said pivot being provided with a slot within which a spring-like element may slide vertically and at the same time may rock on said pivot, a springlike element hearing within said pivot and extending upwardly therefrom and also in a horizontal direction and a spring connected to said support and to the upper end of said spring-like element for pressing the horizontal portion thereof against the upper edges of sinkers.

'7. A sinker cam assembly for use in knitting machines of the type described including a support, a cam for bearing upon the upper edges of sinkers, a. slot cut lengthwise along the lower surface of said cam and a resilient element attached to said cam and support having an extension passing beneath said cam and bearing upon the upper surfaces of sinkers and so constructed that upon abnormal distortion said element will move upwardly within said slot.

I ROBERT H. LAWSON.

WILLIAM L. SMITH, JR. 

